Saving a file

[TyPR124]

I'm making a program that can write RSS files. Now so far everything works right, except one thing, whenever I create a new RSS file (it can open or create a new one), it either doesn't save the file until it exits, which is bad because I need to read the file afterwards. This is my code:

//Headers
#include <iostream>
#include <fstream>
#include <string>

using namespace std;

//Channel info
struct channel {
       string title;
       string desc;
       string link;
       };

//Item info
struct item {
       string title;
       string desc;
       string link;
       string size;
       string type;
       int pos;
       };
       
//Set up Cahnnel and Items
channel chan;
item items[100];

//Other variables
bool inItem = false;
bool inChan = false;
bool inRSS = false;
string fileName;
char fileNameChar[100]; //Because fileName can't be string when used with i/o fstream
bool newFile = false;
string file[500]; //Will store the file by lines for easier accessing/editing
int numLines;
string line; //Used to store individual lines when needed

// Function Prototypes
void insertLine(int pos, string lineInserted);

//Start of program
int main() {
    cout << "RSS File Maker" << endl << "By: TyPR124" << endl << endl;
    cout << "What is the name of the RSS file? (NOTE: \"NEW\" will create a new file)" << endl;
    getline(cin, fileName);
    
    if (fileName == "NEW") {
                 newFile = true;
                 cout << endl << "What should your file be called?" << endl;
                 getline(cin, fileName);
    }
    
    //Check if fileName ends in .xml, add if it doesn't
    //FIRST CHECK MUST BE IF LENGTH IS < 5 B/C ERROR WILL HAPPEN IF TRY TO GET SUBSTR STARTING FROM NEGATIVE #
    if ( (fileName.length() < 5) || (fileName.substr(fileName.length()-4, fileName.length() ) != ".xml") ) {
       fileName = fileName + ".xml";
    }
    //Convert fileName to fileNameChar so it can be used with i/o fstream
    for (int a=0; a<=fileName.length(); a++) {
        fileNameChar[a] = fileName[a];
    }
    
    //Open file for reading/writing (use extend for writing)
    ifstream RSS_read (fileNameChar);
    ofstream RSS_write (fileNameChar, ios::app);
    
    RSS_read.close();
    RSS_write.close();
    
    //If file is new, write channel title, desc, and link
    if (newFile) {
                 RSS_write.open(fileNameChar, ios::app);
                 RSS_write << "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" << endl << "<rss version=\"2.0\">";
                 RSS_write.close();
                 
                 cout << endl << endl << "What is the name of the RSS Channel?" << endl;
                 getline(cin, chan.title);
                 
                 RSS_write.open(fileNameChar, ios::app);
                 RSS_write << endl << endl << "<channel>" << endl << endl;
                 RSS_write << "<title>" << chan.title << "</title>" << endl;
                 RSS_write.close();
                 
                 cout << endl << "What is the description of the RSS Channel?" << endl;
                 getline(cin, chan.desc);
                 
                 RSS_write.open(fileNameChar, ios::app);
                 RSS_write << "<description>" << chan.desc << "</description>" << endl;
                 RSS_write.close();
                 
                 cout << endl << "What is the link to the RSS Channel?" << endl << "NOTE: IT MUST BE A FULL HTTP LINK" << endl;
                 getline(cin, chan.link);
                 
                 RSS_write.open(fileNameChar, ios::app);
                 RSS_write << "<link>" << chan.link << "</link>" << endl;
                 RSS_write.close();
    }
    
    //Save the RSS File in the var. file and find the number of lines
    RSS_read.open(fileNameChar);
    for (int a=0; getline(RSS_read, line); a++) {
        file[a] = line;
        numLines = a; //I won't count the first line as a numbered line because it MUST ALWAYS be the same in RSS files
    }
    
    //Check the first line to make sure it is valid
    if (file[0].substr(0, 18) == "<?xml version=\"1.0\"") {
       file[0] = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>";
    }
    else {
        insertLine(0, "<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
    }
    
    
    //TEST
    for (int a=0; a<=numLines+1; a++) {
        cout << file[a] << endl;
    }
    cin.ignore();
    cin.get();
}


void insertLine(int pos, string lineInserted) {
     string temp[500];
     for (int a=0; a<500; a++) {
         temp[a] = file[a];
     }
     file[pos] = lineInserted;
     
     for (int a = pos+1; a <= numLines+1; a++) {
         file[a] = temp[a-1];
     }
}

The problem seems like it's not saving the file directly after I close it, because if I take out the check of the first line, it couts nothing, but if I leave it in it only couts the first line. And when I open the file it's the way it's supposed to be. So is there a way I can manually save the file? Thanks.

[Elysia]

Don't use global variables.
You can use std::string.c_str() to get a C-style if you need it. I don't think istream or ostream should need a C-style string to open a file.
You can flush a stream to force the output to be written. Dunno how you do it with ostream, though.

[TyPR124]

Whats wrong with global variables? Besides, I would have to use some of them global unless want to constantly pass variables back and forth through functions.

And flush-ing it didn't work. Also, as far as I know, endl is supposed to do the same thing as flush and add a line at the same time anyway... I tried manually changing the numLines before couting to see if that had to do with it, but that just gave me a bunch of blank lines. So now I can't think of anything else that could possibly be wrong with it other than not saving the file right away.

EDIT: I could make a work-around by putting the info for the new file in the array, but then I'm not sure if I'll need to read the file itself later... but if no one can come up with something, I guess thats what I'll have to do.

[Elysia]

Whats wrong with global variables? Besides, I would have to use some of them global unless want to constantly pass variables back and forth through functions.

Then pass them back and forth. Avoid global variables at all costs. Anyone here will tell you the same thing.
Why is this? Because all and every function can modify these, whileas if you pass them as arguments, only the function that gets them can modify them. Common sense. You can also do const on arguments you pass so the functions won't modify them. You can't do that on global variables if you want to modify them.
So avoid them!

[dwks]

And flush-ing it didn't work. Also, as far as I know, endl is supposed to do the same thing as flush and add a line at the same time anyway...

Yes, that's right, for buffered streams. http://www.cplusplus.com/reference/i...tors/endl.html
cout and any files should all be buffered unless you specify otherwise.

I don't think istream or ostream should need a C-style string to open a file.

They do.

std::ifstream compiler_error(std::string("file.txt"));
std::ifstream perfectly_acceptable("file.txt");

[Elysia]

That seems weird to me. Considering the framework is built to accept std::string. Meh, you can still call c_str() anyway.

[TyPR124]

Yeah, I was surprised to find it didn't accept strings, but still an easy fix... Now if only my problem was as easy of a fix (well it probably is, I'm just probably doing something really stupid). I guess I'll put it in the info for the new file in the file variable and continue from there. Hopefully I don't ever need to read the file after that though.

[matsp]

As Elysia said: the designers of std::string did consider that you may want to use it for "old C style string stuff", so if you have a std::string a, you can get a C "char array" string by calling s.c_str(), you don't need to convert it yourself.

--
Mats

[robwhit]

std::string a ... s.c_str()

a or s, not both

[matsp]

Not having a particularly good day today, that's the second typo in about two minutes... Yes, it should be a.c_str() of course.

--
Mats

[dwks]

As Elysia said: the designers of std::string did consider that you may want to use it for "old C style string stuff", so if you have a std::string a, you can get a C "char array" string by calling s.c_str(), you don't need to convert it yourself.

Note that you can't necessary do everything you'd like with std::string::c_str(), because it returns a const string. You can easily make a copy of the string for your own purposes, of course.